The present invention relates generally to a novel construction for awning roller or lead bars, and more particularly concerns a method of constructing roller bars for extendible awnings of the roll-up type popularly utilized with recreational vehicles.
The vigorous pursuit of leisure time activities by Americans has fostered the growth of several diverse industries. Among these industries, the construction of recreational vehicles and their accessories has found a wide market. In particular, trailers, vans and motor homes are favorites with families that enjoy traveling or camping. Extendible awnings have become, in turn, one of the most popular accessories for such recreational vehicles. These awnings generally include a sheet of flexible canopy material secured along one end of the vehicle and secured along the opposite end to a roller bar supported by uprights. Besides the weight of the canopy, wind and precipitation loads further contribute to the stress on the roller bar. Frequently, a valance, screen or sunshade is also attached to the roller bar. To meet the structural requirements, roller bars heretofore have been of extruded or drawn construction. However, roller bars constructed according to the prior art tended to be both heavy and expensive.
The present invention comprises a roller bar construction particularly adapted for use with recreational vehicle awnings which overcomes the foregoing and other problems long since associated with the prior art. In accordance with the broader aspects of the invention, a straight, predetermined length of thin-walled tubing is first provided such as by roll forming the tubing from a sheet of metal. The outer configuration of the tubing provides strength and stiffening, and a reinforcing medium may be provided inside the roller bar, if desired or necessary. By means of this invention, roller bars can be constructed with significant cost and weight savings.
In accordance with more specific aspects of the invention, a section of thin-walled tubing is roll formed from a sheet of metal. Longitudinal profiles are then roll formed into the tubing for partial reinforcement of the tubing to resist bending stresses. However, it will be appreciated that even after formation of the profiles therein, additional reinforcement may be desirable. An expandable material, such as a foamed plastic, is then injected into at least a portion of the space defining the core of the tubing. The expansion and subsequent stabilization of the material into a rigid foam core further strengthens the tubing to provide a strong, light-weight roller bar.
In accordance with another aspect of the invention, the tubing may be roll formed having eight equilateral sidewalls and having a slideway formed along the midregion of at least one of said walls. The roller tubing is formed of a continuous sheet having two longitudinal edges with U-shaped folds for interlocking the edges together to form a closed tubing. Crooks are provided to recess the folds such that the exterior surface of the roller bar is substantially even.
The slideway includes a longitudinal aperture extending along the midregion of one of the equilateral sidewalls. Two slideway walls extend from the edges of the aperture inwardly at about 45.degree. angle with the sidewall. A curved third slideway wall extends between the other two slideway walls to form a substantially triangularly shaped slideway. A plurality of such slideways may be formed in the tubing, and all corners of the roller bar may be rounded.
A roll formed octagonal roller bar with one or more longitudinal slideways will have sufficient strength for many awning applications. However, if additional strengthening is necessary or desirable, a foamed plastic may be injected into at least a portion of the roller bar, or inserts conforming to the shape of the roller bar may be spaced within the bar to provide reinforcement.
The roller bar of the present invention may include one or more longitudinal slideways for attaching awnings, valances, screens and the like to the roller bar. In another embodiment, the roller bar is formed with a continuous exterior surface, and the awning is attached to the roller bar by fasteners or adhesives, or by insertion of the roller bar through a loop sewn on the edge of the awning, or by a combination thereof.